Optical radiation sensor system

ABSTRACT

An optical radiation sensor system having: a housing having a distal portion for receiving radiation from the radiation source and a proximal portion; a sensor element in communication with the proximal portion, the sensor element configured to detect and respond to incident radiation received from the radiation source; and motive structure configured to move the housing with respect to the sensor element between at least a first position and a second position. A radiation pathway is defined between the radiation source and the sensor element when the housing is in at least one of the first position and the second position. Movement of the housing with respect to the sensor element causes a modification of intensity of radiation impinging on the sensor element.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit under 35 U.S.C. §119(e) ofprovisional patent application Ser. No. 60/845,754, filed Sep. 20, 2006,the contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Generally, the present invention relates to an optical radiation sensorsystem.

2. Description of the Prior Art

Optical radiation sensors are known and find widespread use in a numberof applications. One of the principal applications of optical radiationsensors is in the field of ultraviolet radiation fluid disinfectionsystems.

It is known that the irradiation of water with ultraviolet light willdisinfect the water by inactivation of microorganisms in the water,provided the irradiance and exposure duration are above a minimum “dose”level (often measured in units of microwatt seconds per squarecentimetre). Ultraviolet water disinfection units such as thosecommercially available from Trojan Technologies Inc. under thetradenames Trojan UV Max, Trojan UV Swift and UV8000, employ thisprinciple to disinfect water for human consumption. Generally, water tobe disinfected passes through a pressurized stainless steel cylinderwhich is flooded with ultraviolet radiation.

Large scale municipal waste water treatment equipment such as thatcommercially available from Trojan Technologies Inc. under thetrade-names UV3000 and UV4000, employ the same principal to disinfectwaste water. Generally, the practical applications of these treatmentsystems relates to submersion of treatment module or system in an openchannel wherein the wastewater is exposed to radiation as it flows pastthe lamps. For further discussion of fluid disinfection systemsemploying ultraviolet radiation, see any one of the following:

U.S. Pat. No. 4,482,809 [Maarschalkerweerd],

U.S. Pat. No. 4,872,980 [Maarschalkerweerd],

U.S. Pat. No. 5,006,244 [Maarschalkerweerd],

U.S. Pat. No. 5,418,370 [Maarschalkerweerd],

U.S. Pat. No. 5,539,210 [Maarschalkerweerd],

U.S. Pat. No. 5,590,390 (Re. 36,896) [Maarschalkerweerd],

U.S. Pat. No. 7,045,102 [Fraser et al.], and

U.S. patent application Ser. No. 11/078,706 [From et al.].

In many applications, it is desirable to monitor the level ofultraviolet radiation present within the water under treatment. In thisway, it is possible to assess, on a continuous or semi-continuous basis,the level of ultraviolet radiation, and thus the overall effectivenessand efficiency of the disinfection process. The information so-obtainedmay be used to control lamp output to a desired level.

It is known in the art to monitor the ultraviolet radiation level bydeploying one or more sensor devices near the operating lamps inspecific locations and orientations which are remote from the operatinglamps. These sensor devices may be photodiodes, photoresistors or otherdevices that respond to the impingement of the particular radiationwavelength or range of radiation wavelengths of interest by producing arepeatable signal level (e.g., in volts or amperes) on output leads.

In most commercial ultraviolet water disinfection systems, the singlelargest operating cost relates to the cost of electricity to power theultraviolet radiation lamps. In a case where the transmittance of thefluid varies from time to time, it would be very desirable to have aconvenient means by which fluid transmittance could be measured for thefluid being treated by the system (or the fluid being otherwiseinvestigated) at a given time. Indeed, the measurement of fluidtransmittance is a requirement of the United States E.P.A. for municipaldrinking water systems. If it is found that fluid transmittance isrelatively high, it might be possible to reduce power consumption in thelamps by reducing the output thereof. In this way, the significantsavings in power costs would be possible.

The measurement of fluid transmittance is desirable since measurement ofintensity alone is not sufficient to characterize the entire radiationfield—i.e., it is not possible to separate the linear effects of lampaging and fouling from exponential effects of transmittance. Further,dose delivery is a function of the entire radiation field, since not allfluid takes the same path.

First generation optical radiation sensors, by design or orientation,normally sense the output of only one lamp, typically one lamp which isadjacent to the sensor. If it is desirable to sense the radiation outputof a number of lamps, it is possible to use an optical radiation sensorfor each lamp. A problem with this approach is that the use of multiplesensors introduces uncertainties since there can be no assurance thatthe sensors are identical. Specifically, vagaries in sensor materialscan lead to vagaries in the signals which are sent by the sensorsleading to a potential for false information being conveyed to the userof the system.

Another problem with such first generation optical radiation sensors isthat it is not possible to ascertain the lamp output of a single lamp inan array of lamps which operate within the field of view of a singlesensor.

A further problem with such first generation sensors is that, if theU.V. transmittance of the fluid being treated was unknown, two sensorswould be required to determine the dose delivered to the fluid—i.e., onesensor to measure lamp intensity and one sensor to measure U.V.transmittance.

This lead to the development of second generation sensors such as thesensor described in U.S. Pat. No. 6,512,234 [Sasges et al. (Sasges)].The Sasges optical radiation sensor device includes a radiationcollector for receiving radiation from a predefined arc around thecollector within the field and redirecting the received radiation alonga predefined pathway; motive means to move the radiation collector froma first position in which a first portion of the predefined arc isreceived by the radiation collector and a second position in which asecond portion of the predefined arc is received by the radiationcollector; and a sensor element capable of detecting and responding toincident radiation along the pathway when the radiation collector is inthe first position and in the second position.

The Sasges optical radiation sensor represents an important advance inthe art in that it provides for an optical radiation sensor system whichallows determination of lamp output information for a single lamp in anarray of lamps. An additional advantage of the Sasges optical radiationsensor device is that a single sensor device can be used to determinethe dose delivered to the fluid (i.e., in place of the multiple sensorsconventionally required using first generation sensors). Thus, theprovision of the Sasges optical radiation sensor device allows foron-line determination of U.V. transmittance (also known in the art as“UVT”) of the fluid being treated in an ultraviolet radiation lamparray.

Another second generation sensor device is described in U.S. Pat. No.6,818,900 [Ellis et al. (Ellis)]. In its preferred form, the Ellissensor device altered fluid layer thickness between a radiation sourceand a radiation sensor by: (i) moving the radiation source while keepingthe radiation sensor stationary; (ii) moving the radiation sensor whilekeep the radiation source stationary; or (iii) moving a boundary elementinterposed between a stationary radiation source and a stationaryradiation sensor.

Thus, Ellis sensor device requires a single lamp and single sensorelement. The sensor element and radiation source are arranged to createa fluid layer therebetween. By altering the thickness of the fluidlayer, it is possible to take multiple (i.e., two or more) radiationintensity readings at multiple, known fluid layer thicknesses. Oncethese are achieved, using conventional calculations, it is possible toreadily calculate the radiation transmittance of the fluid.

Despite the developments made to date in first and second generationsensors, there is room for improvement. Specifically, it would bedesirable to have an optical radiation sensor system having one or moreof the following features:

-   -   a modular design making the sensor system appropriate for use        with one or more of various radiation sources, fluid thickness        layers and/or UVT conditions;    -   built-in diagnostics for parameters such as sensor operation,        radiation source output, fluid (e.g., water) UVT, radiation        source fouling (e.g., fouling of the protective sleeve        surrounding the radiation source) and the like;    -   incorporation of an integrated reference sensor;    -   relatively safe and ready reference sensor testing;    -   UVT measurement capability; and/or    -   relatively low cost and ease of manufacture.

SUMMARY OF THE INVENTION

It is an object of the present invention to obviate or mitigate at leastone of the above-mentioned disadvantages of the prior art.

It is another object of the present invention to provide a novelradiation sensor system.

Accordingly, in one of its aspects, the present invention provides anoptical radiation sensor system for detecting radiation from a radiationsource, the system comprising:

-   -   a housing having a distal portion for receiving radiation from        the radiation source and a proximal portion;    -   a sensor element in communication with the proximal portion, the        sensor element configured to detect and respond to incident        radiation received from the radiation source; and    -   motive means configured to move the housing with respect to the        sensor element between at least a first position and a second        position, a radiation pathway between the radiation source and        the sensor element being defined when the housing is in at least        one of the first position and the second position;    -   wherein movement of the housing with respect to the sensor        element causes a modification of intensity of radiation        impinging on the sensor element.

In another of its aspects, the present in invention provides an opticalradiation sensor system for detecting radiation from a radiation source,the system comprising:

a housing having a distal portion for receiving radiation from theradiation source and a proximal portion;

a first (e.g, duty) sensor element disposed in the housing;

a second (e.g, reference) sensor element in disposed in the housing, thesecond sensor element configured to detect and respond to incidentradiation received from the radiation source; and

motive means configured to cause radiation from the radiation source toimpinge only on one of the first (e.g., duty) sensor element and thesecond (e.g., reference) sensor element at a given point in time.

In another of its aspects, the present invention provides a fluidtreatment system comprising the present optical radiation sensor system.

In another of its aspects, the present invention provides a watertreatment system comprising the present optical radiation sensor system.

Thus, the present inventors have developed a radiation sensor systemwhich, in its highly preferred embodiment, is of a modular designrendering the sensor system appropriate for use with one or more ofvarious radiation sources, fluid thickness layers and/or in UVTconditions. In this highly preferred form, the sensor system may havebuilt-in diagnostics for parameters such as sensor operation, radiationsource output, fluid (e.g., water) UVT, radiation source fouling (e.g.,fouling of the protective sleeves surrounding the radiation source) andthe like. Other advantages of the present radiation sensor systeminclude: incorporation of an integrated reference sensor, safe and readyreference sensor testing, UVT measurement capability and/or relativelylow cost and ease of manufacture.

A further preferred form of the present radiation sensor system is onein which the housing of the sensor system is moved only between twopositions. In one position, the radiation sensor system operates in aso-called “normal” state. In the second position, the sensor systemoperates in a so-called “test” state wherein the housing (or a portionthereof) is moved to alter the intensity of radiation impinging on thesensor element. Preferably, in the first position, a filter element isdisposed in the pathway between the radiation source and the sensorelement. In the second position wherein the user wishes to test whetherthe sensor element is operating properly, a lever, handle or otherdevice is actuated and the filter element is removed from the radiationpath thereby exposing the radiation element with an increased amount ofradiation. The sensor system contains appropriate diagnostic circuitryto indicate to the user (e.g., via audible and/or visual means) if thesensor element is malfunctioning. In this embodiment, it is preferred touse a so-called neutral density filter whose effectiveness can beselected to obtain any signal ratio required so that a “check” signalwould be detected even at very low (UVT) of the fluid being treated andwith a “dirty” sensor and/or protective sleeve around the radiationsource. In other words, the neutral density filter would block asignificant portion (e.g., 90%) of radiation during normaloperation—i.e., in the first position. This significant portion willdepend, in large part, on the UVT of the fluid be treated in the fluidtreatment system. Once the filter is removed from the radiation path(i.e., the housing is moved to the second position), the use can simplydiagnose if the sensor element is operating properly—i.e., in the secondposition. Specifically, if a change in signal of radiation impinging onthe sensor element is not detected in the “test” position, this would beindicative of sensor element malfunctioning.

Another advantage of the present radiation sensor system is that itfacilitates incorporation of a fully integrated reference sensor. Duringnormal operation the reference sensor normally would not be exposed toradiation since it can be disposed in a “dark zone” of the housing ofthe present radiation sensor system. Such protection of the referencesensor from radiation (e.g., ultraviolet radiation) when not in use willmeet the United States E.P.A. guidelines criteria for reference sensors.The reference sensor checks could be done remotely, and at any time theuser wishes, without: (i) impacting to the operation of the fluidtreatment system, (ii) the potential of exposing the user to radiationsuch as UV-C, or (iii) the need to remove the safety barrier associatedwith having the sensor in the fluid treatment system.

If, during normal operation the standard (“duty”) radiation sensor wereto fail, the reference sensor could then be used to measure lampintensity, and UVT (in the case of water treatment) until theappropriate repairs were made. The user would most likely never bewithout an operational sensor.

Preferably, the reference sensor (if present) is embodied in theaddition of a second photodiode onto a PCB allowing it to performreference checks (which are required under certain regulations). Whetherthere are 2 separate circuits or 1 circuit for both sensor elements willdepend on the application. For instance, having 2 sensor elementsconnect to one single circuit would permit the checking of degradationof the “duty” or most used sensor element. The second or “reference”diode would be shielded from radiation to ensure that degradation of thesecond diode from exposure to radiation is eliminated. It is possible tohave each sensor element connected to dedicated circuitry. While thiswould require more space on the PCB and more electrical connections tobe used, the advantage is that the user may individually calibrate bothsensor elements and respective circuitry. By having both sensor elementsattached to one circuit, the user, in effect, would be checking theuncertainty of the sensor “detectors” itself and removing the circuitryfrom the uncertainty. The reference sensor is disposed on a PCB whichpreferably is configured to move the reference sensor to the positionnormally occupied by the “duty” sensor from time to time.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will be described withreference to the accompanying drawings, in which:

FIG. 1 illustrates a fluid treatment system incorporating an embodimentof the present optical radiation sensor system;

FIGS. 2-6 illustrate detailed views of the radiation sensor system shownin FIG. 1;

FIGS. 7-11 illustrate various views of an embodiment of the presentradiation sensor system suitable for use with a movable block;

FIG. 12 illustrates an alternate embodiment of the block shown in FIGS.7-11;

FIG. 13 illustrates the blocks shown in FIGS. 7-12 in a comparativefashion; and

FIGS. 14-15 illustrate the block shown in FIGS. 7-11 incorporated withother elements in a preferred embodiment of the present radiation sensorsystem.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, there is illustrated a fluid treatment system10 comprising a housing 15 having an inlet 20 and an outlet 25. Housing15 comprises a pair of end walls 30,35. Disposed in each end wall 30,35is a mounting sleeve 40. As illustrated, mounting sleeves 40 supportopposed ends of a radiation source (preferably an ultraviolet radiationsource) 45. It will be apparent that radiation source 45 is elongate andcomprises a longitudinal axis. As will be understood by those of skillin the art, it is conventional to dispose radiation source 45 in aradiation transparent protective (e.g., quartz) sleeve which has beenomitted from the drawings of the present application for clarity.

The description of fluid treatment system 10 up to this point isconventional. It will be recognized that fluid treatment system 10 is aso-called disposed system wherein fluid being treated is confined on allsurfaces as it passes through housing 15.

Disposed in housing 15 is a first embodiment of the present radiationsensor system 100.

FIG. 2 illustrates an enlarged portion of fluid treatment system 10showing mounting of radiation sensor system 100 in the wall of housing15.

With reference to FIGS. 2-6, radiation sensor system 100 will bedescribed in more detail.

Radiation sensor system 100 comprises a housing 105 in which is receiveda slidable member 110. Slidable member 110 comprises a handle portion115 which can be gripped by a user who wishes to check whether radiationsensor system 100 is functioning properly.

Slidable member 115 comprises a first passageway 120 and a secondpassageway 125. First passageway 120 is open in that there is noobstruction place therein. Disposed in or in front of or at the rear ofpassageway 125 is a neutral density filter 127 capable of filtering atleast a portion of radiation impinging thereon. Preferably, neutraldensity filter is constructed from a metal mesh. Alternatively, thefunction of the neutral density filter is conferred by using: (i)alternative thickness of a radiation transparent material such as quartzglass, (ii) a heavy metal oxide filter, or (iii) a UV transparent Teflonmaterial.

Also disclosed in housing 105 is a spring element 130 which is adjacentan end portion 135 of slidable member 110.

Connected to housing 105 is a sub-housing 140 consisting of a series ofsleeve bolts, O-rings and a cover 150 which is disposed in the fluidbeing treated in fluid treatment system 10. Cover 150 comprises aradiation transparent window 155 which allows radiation impinging onwindow 155 to pass therethrough.

A radiation sensor element 160 is disposed in housing 105 such that itis in substantial alignment with window 155 of cover 150. Sensor element160 can be of any conventional type such as silicon, silicon carbide,diamond and the like.

FIG. 4 illustrates radiation sensor system 100 in the so-called “normal”position in which aperture 125 comprising filter element 127 is alignedwith window 155 of cover 150. During operation of fluid treatment system10, radiation emanating from radiation source 45 is received insub-housing 140 and is filtered by filter element 127 such that only aportion of the radiation impinges on sensor element 160. Sensor element160 is connected to a circuit board 165 which contains conventionalcircuitry (not shown) for sensor element 160 and is connected to one orboth of an audio interface and a video interface (not shown) so as toalert the user about operation of radiation sensor system 100.

When a user wishes to test whether radiation sensor system 100 isoperating properly, the user simply grips handle portion 115 and pushesslidable member 110 toward spring 130 to compress the latter—this isshown in FIG. 5. In this position, aperture 120 (containing no filter)is aligned with window 155 of cover 150 allowing a significantlyincreased amount of radiation to impinge on sensor element 160. Such anoperation would allow the user to simply diagnose whether a loss ofsensor signal is related to circuit board 165, the UVT of the fluidbeing treated or, after cleaning the exterior radiation source 45,related to fouling of the radiation source.

After the test is complete, the user simply releases handle 115 andslidable member 110 is biased to the so-called “normal” operatingposition—i.e., as shown in FIG. 4.

Thus, it will become apparent to those of skill in the art, that atleast one element of housing 105 is configured to move with respect tosensor element 160 between a first position (FIG. 4) and a secondposition (FIG. 5). In the first position, aperture 125 (containingneutral density filter 127) is aligned with window 155 so that radiationfrom radiation source 45 passes through aperture 125. In the secondposition, aperture 120 is aligned with window 155 of cover 150 therebyallowing radiation from radiation source 45 to pass through in arelatively unobstructed manner and impinge on sensor element 160.

Radiation sensor system 100 described above is well suited for use inmost radiation-based fluid treatment systems such as ultravioletradiation water treatment system, particularly those configured forresidential use in the treatment of potable water.

Radiation sensor system 100 is operable by having an element of housing105 operable between a first position (FIG. 4) and a second position(FIG. 5) as described above. In essence, the transition from the firstposition to the second position involves altering the radiation pathwaybetween radiation source 45 and sensor element 160 so as to modify theintensity of radiation impinging on sensor element 160. In thespecifically illustrated embodiment, this achieved by using movingslidable member 110 to extend neutral density filter 127 out of theradiation pathway to create a radiation pathway having no such filterelement.

Those of skill in the art will appreciate that such functionality can beachieved by modifying radiation sensor system 100, for example in amanner whereby slidable member 110 is configured to retract neutraldensity filter 127 toward the user to create a radiation pathway havingno such filter element. It is also possible modify the plunger design ofslidable member 110 in housing 105 to use a lift lever connected to arotatable housing containing a pair of intersecting pathways anddisposing the neutral density filter in one of the pathways (away fromthe intersection of the pathways).

Radiation sensor system 100 embodies the basic functionality of allowinga user to quickly and easily ascertain whether fluid treatment system 10is operating properly (e.g., the prescribed radiation dose is beingdelivered by radiation source 45 to fluid passing through housing 15).This renders radiation system 100 useful in virtually all fluidtreatment systems such as ultraviolet radiation water treatment systems(including those described above).

In some cases, it may desirable to add one or more radiation pathways tothe radiation sensor system wherein each such radiation pathway providesan additional functionality to the radiation sensor system. For exampleit is possible to configure the radiation sensor system to include ablock that is moveable between a number of positions equivalent to thenumber of radiation pathways. In practice, a single pathway would existbetween the radiation source (or sources) and the sensor element. Theintensity of radiation impinging on the radiation sensor would bemodified by moving the block thereby moving various elements in or outof the pathway. The block may be moved by translation (slidable),rotation or any other convenient means.

For example, it is possible to configure the movable block to have twoor more block pathways (each pathway is configured to function in thefollowing manner and/or include elements to achieve the statedfunctionality):

-   -   Pathway (A): the distal portion of the block is configured to be        positioned at a first distance from the radiation source and        comprises a first filter element interposed between the distal        portion and the sensor element, the first filter element        configured to filter prescribed radiation wavelengths (e.g., the        neutral density filter described above);    -   Pathway (B): the distal portion of the block is configured to be        positioned at a first distance from the radiation source and        does not contain the first filter element in block Pathway (A);    -   Pathway (C): the distal portion of the block is configured to be        positioned at a second distance from the radiation source and        comprises a second filter element interposed between the distal        portion and the sensor element, the second filter element        configured to filter a prescribed radiation wavelength (e.g.,        the neutral density filter described above), the second distance        being less that the first distance in Pathway (A);    -   Pathway (D): the distal portion of the block is configured to be        positioned at the second distance from the radiation source and        does not contain the second filter element in block Pathway (C);    -   Pathway (E): a radiation opaque element is interposed between        the distal portion of the block and the sensor element, the        radiation opaque element configured to prevent substantially all        radiation from the radiation source from impinging on the sensor        element;    -   Pathway (F): a radiation opaque element is interposed between        the distal portion of the block and the sensor element, the        radiation opaque element being configured to prevent        substantially all radiation from the radiation source from        impinging on the sensor element; and a first supplementary        radiation source is interposed between the radiation opaque        element, the supplementary radiation source being configured to        emit radiation at an intensity that exceeds the detection limit        of the sensor element;    -   Pathway (G): a radiation opaque element is interposed between        the distal portion of the block and the sensor element, the        radiation opaque element being configured to prevent        substantially all radiation from the radiation source from        impinging on the sensor element; and a second supplementary        radiation source is interposed between the radiation opaque        element, the supplementary radiation source being configured to        emit radiation at a prescribed intensity below a pre-determined        detection limit of the sensor element.

Preferably, the distal portion of the block in Pathway (E) is positionedat the first distance from the radiation source.

Preferably, the distal portion of the block in Pathway (F) is positionedat the first distance from the radiation source.

Preferably, the distal portion of the block in Pathway (G) is positionedat the first distance from the radiation source.

Preferably, the distal portion of the block in Pathway (E) is positionedat the second distance from the radiation source.

Preferably, the distal portion of the block in Pathway (F) is positionedat the second distance from the radiation source.

Preferably, the distal portion of the block in Pathway (G) is positionedat the second distance from the radiation source.

Those of skill in the art will recognize that the precise position ofthe distal portion of the block in Pathways (E), (F) and (G) withrespect to the radiation source is not particularly restricted sinceeach of these Pathways contains a radiation opaque element.

In a first preferred embodiment the block comprises at least one ofPathways (A) and (B), more preferably at least each of Pathways (A) and(B). Such an arrangement provides the same functionality as radiationsensor system 100 described above. The arrangement is well suited foruse with a radiation sensor system in a water treatment system which istreating water over a relatively narrow UVT range (e.g, drinking orpotable water).

In a second preferred embodiment, the block comprises at least one ofPathways (C) and (D), preferably each of Pathways (C) and (D). Such anarrangement provides the same functionality as radiation sensor system100 described above. Since the distal portion of the block in Pathways(C) and (D) is at lesser distance to the radiation source than that ofPathways (A) and (B), Pathways (C) and (D) provide the additionaladvantage of being able to use the radiation sensor system in watertreatment system which is treating water over a relatively broad UVTrange (e.g., municipal waste water).

In a third preferred embodiment, the block comprises at least Pathways(A) and (C) or at least Pathways (B) and (D), preferably each ofPathways (A), (B), (C) and (D). This preferred embodiment embodies thefunctionality of allowing the user to measure the UVT of the water beingtreated (e.g, in an on-line manner) by obtaining multiple radiationintensity readings at multiple water layer thickness—see, for example,U.S. Pat. No. 6,512,234 for additional information on how to convertso-obtained multiple radiation intensity readings to UVT. In thisembodiment, a comparison of radiation intensity readings using Pathways(A) and (C) may be used when treating relatively high UVT water (e.g,drinking or potable water) and a comparison of radiation intensityreadings using Pathways (B) and (D) may be used when treating relativelylow UVT water (e.g, municipal waste water).

In a fourth preferred embodiment, the block comprises the first, secondor third preferred embodiments just described, together with at leastone of Pathways (E), (F) and (G), more preferably together with at leasttwo of Pathways (E), (F) and (G), even more preferably together witheach of Pathways (E), (F) and (G).

Pathway (E) is a so-called “dark zone” in which the sensor element maybe placed for a 4 ma (i.e., nil) signal check.

Preferably, the first supplementary radiation source in Pathway (F) is alight emitting diode such as a UV-C light emitting diode. In essencethis pathway is similar to Pathway (E) with the addition of a UV-C lightemitting diode (preferred embodiment) in a portion of the dark zoneproviding for the ability to conduct a saturation signal check on thesensor element. An advantage of Pathway (F) is that it allows forremoval of the sensor element from the fluid treatment system from thesensor check.

Preferably, the second supplementary radiation source in Pathway (G) isa light emitting diode such as a UV-C light emitting diode. SincePathway (F) represents a dark zone for the sensor element, a second (orthe same) pathway with output from a calibrated UV-C light emittingdiode (preferred embodiment) could be used to check one set point on theoperational curve of the sensor. For example: if at the time ofcalibration, the set point light emitting diode were known to generate asignal of 11 mA in the sensor element, sensor operation could becompared to this value at any time during system operation which wouldthen help determine whether the radiation sensor system was workingwithin expected parameters. This is especially advantageous as it is apure check of the performance of the sensor electronics in that theadditional variables of tolerance stack up, lamp output variability,quartz sleeve and fouling are removed.

FIGS. 7-11 illustrate various views of an embodiment of the presentradiation sensor system suitable for use with a block 200 having adistal end 205 and a proximal end 210. Block 200 is connected to a motor(not shown) or other motive means that rotates with respect to a sensorelement 215 and a radiation source 220 to alter the intensity ofradiation impinging on sensor element 215 in the manner described above.It is possible of course to eliminate the motor such that block 200 isrotated manually. The letters A, B, C, D, E, F and G have been used todenote the Pathways described above.

FIG. 12 illustrates an alternative embodiment in which the samefunctionality is achieved with a block 200 a have a distal end 205 a andproximal end 210 a. Block 200 a is connected to a motor (not shown) orother motive means that translates block 200 a with respect to sensorelement 215 and radiation source 220. While the means of moving thereference sensor (if present) is not specifically shown in the drawings,this can be readily accomplished by those of skill in the art.

FIG. 13 illustrates block 200 in an “unrolled” fashion and block 200 ato show the equivalent functionality of these elements.

In FIGS. 7-13, the letters A, B, C, D, E, F and G have been used todenote the Pathways described above.

With reference to FIGS. 14 and 15, there is illustrated block 200 (FIGS.7-11) incorporated with other elements in a preferred embodiment of thepresent radiation sensor system. Proximal end 210 of block 200 isdisposed in a housing 250 which also contains sensor element 215 (forclarity, neither proximal end 210 nor sensor element 215 are shown inFIGS. 14 and 15).

Connected to the distal end 205 of block 200 is a cleaning system 255consisting of cleaning chambers 260,265. A rubber (or similar) gasket270 is interposed between cleaning chambers 260,265 and distal end 205of block 200. Cleaning chambers 260, 265 may be filled with a suitablecleaning fluid. Cleaning system 255 further comprises a conduit 257 forsupply cleaning fluid to each of cleaning chambers 260,265.

Cleaning system 255 is connected to an axle 258 which in turn isconnected a linear solenoid 270 via an arm 268. Housing 250 is connectedto linear solenoid 270 via a mount 275.

When it is desired to clean the distal end 205 of block 200, solenoid270 is actuated and cleaning system 255 is rotated in the direct ofarrow Y. Thus, cleaning system 255 essentially is operable between afirst position (FIG. 14) and a second position (FIG. 15).

While this invention has been described with reference to illustrativeembodiments and examples, the description is not intended to beconstrued in a limiting sense. Thus, various modifications of theillustrative embodiments, as well as other embodiments of the invention,will be apparent to persons skilled in the art upon reference to thisdescription. It is therefore contemplated that the appended claims willcover any such modifications or embodiments.

All publications, patents and patent applications referred to herein areincorporated by reference in their entirety to the same extent as ifeach individual publication, patent or patent application wasspecifically and individually indicated to be incorporated by referencein its entirety.

1. An optical radiation sensor system for detecting radiation from aradiation source, the system comprising: a housing having a distalportion for receiving radiation from the radiation source and a proximalportion; a sensor element in communication with the proximal portion,the sensor element configured to detect and respond to incidentradiation received from the radiation source; and motive meansconfigured to move the housing with respect to the sensor elementbetween at least a first position and a second position, a radiationpathway between the radiation source and the sensor element beingdefined when the housing is in at least one of the first position andthe second position; wherein movement of the housing with respect to thesensor element causes a modification of intensity of radiation impingingon the sensor element; and wherein the housing is configured to bepositioned at: (i) a first distance from radiation source in the firstposition, and (ii) a second distance from the radiation source in thesecond position, the first distance being different than the seconddistance.
 2. The radiation sensor system defined in claim 1, wherein thefirst position comprises a first radiation filter element and the secondposition is free of the first radiation filter element present in thefirst position.
 3. The radiation sensor system defined in claim 1,wherein a first radiation pathway from the radiation source to thesensor element is defined when the housing is in the first position. 4.The radiation sensor system defined in claim 1, wherein a secondradiation pathway from the radiation source to the sensor element isdefined when the housing is in the second position.
 5. The radiationsensor system defined in claim 1, wherein a first radiation pathway fromthe radiation source to the sensor element is defined when the housingis in the first position and a second radiation pathway from theradiation source to the sensor element is defined when the housing is inthe second position.
 6. The radiation sensor system defined in claim 1,wherein a first radiation pathway from the radiation source to thesensor element is defined when the housing is in the first position andthe housing further comprises a radiation opaque element which preventssubstantially all radiation from the radiation source from impinging onthe sensor element when the housing is in the second position.
 7. Theradiation sensor system defined in claim 6, further comprising asupplementary radiation source disposed between the radiation opaqueelement and the sensor element.
 8. The radiation sensor system definedin claim 7, wherein the supplementary radiation source is configured toemit radiation at a pre-determined detection limit of the sensorelement.
 9. The radiation sensor system defined in claim 7, wherein thesupplementary radiation source is configured to emit radiation at aprescribed intensity below pre-determined detection limit of the sensorelement.
 10. The radiation sensor system defined in claim 1, wherein thehousing is configured as a block comprising a multiplicity of differentblock pathways between the distal portion and the proximal portion, theblock being moveable with respect to the sensor element to a positioncorresponding to each block pathway.
 11. The radiation sensor systemdefined in claim 10, wherein the block comprises at least two blockpathways selected from the group consisting of: (A) the distal portionbeing positioned at a first distance from the radiation source andcomprising a first filter element interposed between the distal portionand the sensor element, the first filter element configured to filterprescribed radiation wavelengths; (B) the distal portion beingpositioned at a first distance from the radiation source and being freeof the first filter element in block pathway (A); (C) the distal portionbeing positioned at a second distance from the radiation source andcomprising a second filter element interposed between the distal portionand the sensor element, the second filter element configured to filterprescribed radiation wavelengths, the second distance being less thatthe first distance in pathway (A); (D) the distal portion beingpositioned at the second distance from the radiation source and beingfree of the second filter element in block pathway (C); (E) a radiationopaque element interposed between the distal portion of the housing andthe sensor element, the radiation opaque element configured to preventsubstantially all radiation from the radiation source from impinging onthe sensor element; (F) a radiation opaque element interposed betweenthe distal portion of the housing and the sensor element, the radiationopaque element being configured to prevent substantially all radiationfrom the radiation source from impinging on the sensor element; and afirst supplementary radiation source interposed between the radiationopaque element, the supplementary radiation source being configured toemit radiation at an intensity that exceeds the detection limit of thesensor element; (G) a radiation opaque element interposed between thedistal portion of the housing and the sensor element, the radiationopaque element being configured to prevent substantially all radiationfrom the radiation source from impinging on the sensor element; and asecond supplementary radiation source interposed between the radiationopaque element, the supplementary radiation source being configured toemit radiation at a prescribed intensity below a predetermined detectionlimit of the sensor element.
 12. The radiation sensor system defined inclaim 11, wherein the distal portion of the housing in pathway (E) ispositioned at the first distance from the radiation source.
 13. Theradiation sensor system defined in claim 11, wherein the distal portionof the housing in pathway (F) is positioned at the first distance fromthe radiation source.
 14. The radiation sensor system defined in claim11, wherein the distal portion of the housing in pathway (G) ispositioned at the first distance from the radiation source.
 15. Theradiation sensor system defined in claim 11, wherein the distal portionof the housing in pathway (E) is positioned at the second distance fromthe radiation source.
 16. The radiation sensor system defined in claim11, wherein the distal portion of the housing in pathway (F) ispositioned at the second distance from the radiation source.
 17. Theradiation sensor system defined in claim 11, wherein the distal portionof the housing in pathway (G) is positioned at the second distance fromthe radiation source.
 18. The radiation sensor system defined in claim11, wherein the first supplementary radiation source is a first lightemitting diode.
 19. The radiation sensor system defined in claim 11,wherein the second supplementary radiation source is a second lightemitting diode.
 20. The radiation sensor system defined in claim 11,wherein the first supplementary radiation source is a first lightemitting diode and the second supplementary radiation source is a secondlight emitting diode.
 21. The radiation sensor system defined in claim11, wherein the block comprises at least one of pathways (A) and (B).22. The radiation sensor system defined in claim 21, wherein the blockfurther comprises at least two of pathways (E), (F) and (G).
 23. Theradiation sensor system defined in claim 21, wherein the block furthercomprises each of pathways (E), (F) and (G).
 24. The radiation sensorsystem defined in claim 11, wherein the block comprises at least each ofpathways (A) and (B).
 25. The radiation sensor system defined in claim11, wherein the block comprises at least one of pathways (C) and (D).26. The radiation sensor system defined in claim 11, wherein the blockcomprises at least each of pathways (C) and (D).
 27. The radiationsensor system defined in claim 11, wherein the block comprises at leastone of pathways (A) and (C).
 28. The radiation sensor system defined inclaim 11, wherein the block comprises at least each of pathways (B) and(D).
 29. The radiation sensor system defined in claim 21, wherein theblock further comprises at least one of pathways (E), (F) and (G). 30.The radiation sensor system defined in claim 11, wherein the blockcomprises each of pathways (A), (B), (C), (D), (E), (F) and (G).
 31. Anoptical radiation sensor system for detecting radiation from a radiationsource, the system comprising: a housing having a distal portion forreceiving radiation from the radiation source and a proximal portion; asensor element in communication with the proximal portion, the sensorelement configured to detect and respond to incident radiation receivedfrom the radiation source; and motive means configured to move thehousing with respect to the sensor element between at least a firstposition and a second position, a radiation pathway between theradiation source and the sensor element being defined when the housingis in at least one of the first position and the second position;wherein: (i) the housing is configured as a block comprising amultiplicity of different block pathways between the distal portion andthe proximal portion, the block being moveable with respect to thesensor element to a position corresponding to each block pathway tocause a modification of intensity of radiation impinging on the sensorelement; and (ii) wherein the block comprises at least two blockpathways selected from the following pathways (A) and (B), incombination with at least one block pathway selected from the followingpathways (B), (F) and (G), where: (A) the distal portion beingpositioned at a first distance from the radiation source and comprisinga first filter element interposed between the distal portion and thesensor element, the first filter element configured to filter prescribedradiation wavelengths; (B) the distal portion being positioned at afirst distance from the radiation source and being free of the firstfilter element in block pathway (A); (C) the distal portion beingpositioned at a second distance from the radiation source and comprisinga second filter element interposed between the distal portion and thesensor element, the second filter element configured to filterprescribed radiation wavelengths, the second distance being less thatthe first distance in pathway (A); (D) the distal portion beingpositioned at the second distance from the radiation source and beingfree of the second filter element in block pathway (C); (E) a radiationopaque element interposed between the distal portion of the housing andthe sensor element, the radiation opaque element configured to preventsubstantially all radiation from the radiation source from impinging onthe sensor element; (F) a radiation opaque element interposed betweenthe distal portion of the housing and the sensor element, the radiationopaque element being configured to prevent substantially all radiationfrom the radiation source from impinging on the sensor element; and afirst supplementary radiation source interposed between the radiationopaque element, the supplementary radiation source being configured toemit radiation at an intensity that exceeds the detection limit of thesensor element; (G) a radiation opaque element interposed between thedistal portion of the housing and the sensor element, the radiationopaque element being configured to prevent substantially all radiationfrom the radiation source from impinging on the sensor element; and asecond supplementary radiation source interposed between the radiationopaque element, the supplementary radiation source being configured toemit radiation at a prescribed intensity below a predetermined detectionlimit of the sensor element.
 32. The radiation sensor system defined inclaim 31, wherein the distal portion of the housing in pathway (E) ispositioned at the first distance from the radiation source.
 33. Theradiation sensor system defined in claim 31, wherein the distal portionof the housing in pathway (F) is positioned at the first distance fromthe radiation source.
 34. The radiation sensor system defined in claim31, wherein the distal portion of the housing in pathway (G) ispositioned at the first distance from the radiation source.
 35. Theradiation sensor system defined in claim 31, wherein the distal portionof the housing in pathway (E) is positioned at the second distance fromthe radiation source.
 36. The radiation sensor system defined in claim31, wherein the distal portion of the housing in pathway (F) ispositioned at the second distance from the radiation source.
 37. Theradiation sensor system defined in claim 31, wherein the distal portionof the housing in pathway (G) is positioned at the second distance fromthe radiation source.
 38. The radiation sensor system defined in claim31, wherein the first supplementary radiation source is a first lightemitting diode.
 39. The radiation sensor system defined in claim 31,wherein the second supplementary radiation source is a second lightemitting diode.
 40. The radiation sensor system defined in claim 31,wherein the first supplementary radiation source is a first lightemitting diode and the second supplementary radiation source is a secondlight emitting diode.
 41. The radiation sensor system defined in claim31, wherein the block comprises each of pathways (A) and (B).
 42. Theradiation sensor system defined in claim 31, wherein the block furthercomprises at least one of pathways (C) and (D).
 43. The radiation sensorsystem defined in claim 31, wherein the block further comprises each ofpathways (C) and (D).
 44. The radiation sensor system defined in claim31, wherein the block comprises one of pathways (A) and (C).
 45. Theradiation sensor system defined in claim 31, wherein the block compriseseach of pathways (B) and (D).
 46. The radiation sensor system defined inclaim 31, wherein the block comprises at least two of pathways (E), (F)and (G).
 47. The radiation sensor system defined in claim 31, whereinthe block comprises each of pathways (E), (F) and (G).
 48. The radiationsensor system defined in claim 31, wherein the block comprises each ofpathways (A), (B), (C), (D), (E), (F) and (G).